Re: [PATCH 6.16.y 2/2] dt-bindings: serial: 8250: allow "main" and "uart" as clock names

[Alex Elder <elder@riscstar.com>]

On 9/17/25 6:55 AM, Sasha Levin wrote:
> From: Alex Elder <elder@riscstar.com>
> 
> [ Upstream commit a1b51534b532dd4f0499907865553ee9251bebc3 ]
> 
> There are two compatible strings defined in "8250.yaml" that require
> two clocks to be specified, along with their names:
>    - "spacemit,k1-uart", used in "spacemit/k1.dtsi"
>    - "nxp,lpc1850-uart", used in "lpc/lpc18xx.dtsi"
> 
> When only one clock is used, the name is not required.  However there
> are two places that do specify a name:
>    - In "mediatek/mt7623.dtsi", the clock for the "mediatek,mtk-btif"
>      compatible serial device is named "main"
>    - In "qca/ar9132.dtsi", the clock for the "ns8250" compatible
>      serial device is named "uart"
> 
> In commit d2db0d7815444 ("dt-bindings: serial: 8250: allow clock
> 'uartclk' and 'reg' for nxp,lpc1850-uart"), Frank Li added the
> restriction that two named clocks be used for the NXP platform
> mentioned above.
> 
> Change that logic, so that an additional condition for (only) the
> SpacemiT platform similarly restricts the two clocks to have the
> names "core" and "bus".
> 
> Finally, add "main" and "uart" as allowed names when a single clock is
> specified.
> 
> Fixes: 2c0594f9f0629 ("dt-bindings: serial: 8250: support an optional second clock")
> Cc: stable <stable@kernel.org>
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202507160314.wrC51lXX-lkp@intel.com/
> Signed-off-by: Alex Elder <elder@riscstar.com>
> Acked-by: Conor Dooley <conor.dooley@microchip.com>
> Link: https://lore.kernel.org/r/20250813031338.2328392-1-elder@riscstar.com
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Sasha Levin <sashal@kernel.org>

This fix looks good.

Acked-by: Alex Elder <elder@riscstar.com>

> ---
>   Documentation/devicetree/bindings/serial/8250.yaml | 10 +++++++++-
>   1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/serial/8250.yaml b/Documentation/devicetree/bindings/serial/8250.yaml
> index 2766bb6ff2d1b..c1c8bd8e8dde6 100644
> --- a/Documentation/devicetree/bindings/serial/8250.yaml
> +++ b/Documentation/devicetree/bindings/serial/8250.yaml
> @@ -60,7 +60,12 @@ allOf:
>             items:
>               - const: uartclk
>               - const: reg
> -    else:
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: spacemit,k1-uart
> +    then:
>         properties:
>           clock-names:
>             items:
> @@ -162,6 +167,9 @@ properties:
>       minItems: 1
>       maxItems: 2
>       oneOf:
> +      - enum:
> +          - main
> +          - uart
>         - items:
>             - const: core
>             - const: bus